Studies on equine recurrent uveitis. II: The role of infection with Leptospira interrogans serovar pomona.

This research focuses on the potential link between infection with the Leptospira interrogans serovar pomona bacteria and its correlation with equine recurrent uveitis, a common cause of blindness in horses. The study used a specific type of test to detect antibody presence related to this bacteria in both the blood serum and eye fluids of horses, without finding a significantly higher presence in horses showing uveitis symptoms. In this context, the study emphasizes the complexities of understanding the true causes of equine recurrent uveitis, suggesting that various factors may contribute.

Development of an ELISA Test

• The researchers developed an Enzyme-Linked Immunosorbent Assay (ELISA) specifically to identify antibodies related to the Leptospira interrogans serovar pomona bacteria in horse serum and aqueous humor (eye fluid).
• In addition to the ELISA test, the serum antibody levels were evaluated using microscopic agglutination tests, a standard method to measure the amount of antibodies in a serum sample. These tests help identify current or past infection with Leptospira.

Data Gathering and Analysis

• The study involved collecting and analyzing samples from 101 horses at a slaughterhouse.
• In these samples, antibodies related to the bacteria were detected in the eye fluid of 12 horses.
• The ratios between the aqueous/serum antibody level and the total aqueous/serum IgG level—a measure of immune response—in most of these cases suggested that the antibodies were produced within the eyes (intraocular antibody synthesis). This is an essential observation as it suggests that the bacteria might be directly involved in causing an inflammatory response in the eye.

Further Findings

• Scientists also evaluated nine samples from horses diagnosed with clinically documented uveitis. In four of these samples, antibodies were present.
• The comparison of aqueous/serum antibody level to that of the total aqueous/serum IgG level indicates that these antibodies were produced intraocularly, providing further evidence of the bacteria’s possible role in equine recurrent uveitis.

Study Conclusions

• The data of the study suggests a connection between Leptospira interrogans serovar pomona bacteria and equine recurrent uveitis. However, it also emphasizes the fact that the primary cause of this disease often remains unclear as association with leptospirosis could not be established in many instances.
• The research opens up for more in-depth studies on the matter to achieve clear causal relationships between bacteria like Leptospira and equine recurrent uveitis, which might help develop more effective treatments in the future.